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Records obtained on a microwave relay system south of Lake Michigan indicate that significant attenuation can occur during rainfall at frequencies as low as 7-8 GHz. Prolonged outages axe possible when a squall line moves along, rather than across, a relay system.
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This paper describes a speech predictive encoding communications (SPEC) system that is designed to accommodate the traffic of PCM telephone trunks in the capacity of PCM telephone channels. The system exploits the statistics of multichannel voice communication in a manner significantly different from the technique em...
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This paper investigates the problem of estimating the effects of interference to a coherent phase-shift-keyed (CPSK) digital carrier. Paralleling Saltzberg [1], the principal tool utilized is the CramérChernoff bounding technique. The interference effects can be characterized by equating the larger interferers to an equivalent coherent canceling sine wave and the remaining interferers to an e...
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A new spread spectrum technique using band-limited Gaussian noise for transmission and incoherent detection at the receiver has been discussed. The proposed system called noise band shift keying (NBSK) may be considered as a modified form of the frequency-shift keying (FSK) system. In the NBSK system nonoverlapping bandlimited noise is transmitted instead of pure tones as in the FSK system and the...
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This paper derives the power spectrum of a modulating scheme under consideration by NASA for commanding scientific satellites. In this scheme the commands are frequency-shift keyed onto a subcarrier, then the clock is amplitude modulated onto the resultant. This PCM/FSK-AM waveform is then phase modulated onto a prime carrier. The method used in the paper can be easily extended to derive the spect...
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This paper describes a new method for analyzing the acquisition behavior of a second-order generalized tracking system in the absence of noise. In particular it allows closed-form expressions of the pull-in range and of the frequency acquisition time for any type of loop nonlinearity. The results of the present analysis are compared with those already known in the literature and with others obtain...
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Expressions for calculating the magnitudes and frequencies of jitter components due to the pulse stuffing process are derived by means of a Fourier transform of the pulse stuffing jitter waveform (PSJW) for the cases where the housekeeping bit does and does not affect the stuffed positions. Previously, the latter case has always been assumed. The difference between the two cases is a function of t...
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The grade of service of an alternate route is normally based on the average of several hourly blocking probabilities of the alternate route. The contemporary method for estimating the grade of service of an alternate route requires adjustment to the average traffic loads with appropriate correction factors in order to gain sufficient accuracy. This paper introduces the equivalent trunks technique,...
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A model of a digital data message switching network is described. The network permits only finite storage at nodes. Discussed is a routing strategy and storage allocation to maximize throughput between many source-receiver pairs simultaneously.
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Certain properties of periodic signals are defined in terms of the zeros and singularities of associated analytic functions of a complex time variable . This algebraic approach is a generalization of analytic signal theory, and leads to the conception of hybrid modulation as the superposition of two -plane zero-singulari...
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An analytical formula for the amplitude density of an almost periodic single-tone amplitude-modulated (AM) waveform is presented along with an analytical procedure to obtain the amplitude density for a periodic single-tone AM signal.
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The performance of a maximum likelihood receiver whose input is the photoelectric current created by a modulated light beam is studied for a number of discrete modulation schemes. The performance is compared with that of a classical microwave receiver, i.e., one designed to optimize detection in a Gaussian channel. Such a receiver has the advantages of availability, simplicity, ease of implementat...
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The computation of expected values of functions of quantized random variables is treated by sampling theory methods, as an extension of Widrow's work on the statistical theory of quantization. It is shown that such expected values can often be evaluated readily when conditions analogous to Nyquist sampling constraints are satisfied. An example-computation of the autocorrelation of a phase-quantize...
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